In the forward modeling of transient electromagnetic response, the commonly used method is to calculate the response in the frequency domain, and then the results were converted into the time domain. In this paper, five frequency-time conversion methods (Digital filtering algorithms of sine and cosine transform, G-S inverse Laplace algorithm, polygonal approximations method of sine and cosine transform) were used to conduct calculation. it is concluded that the digital filtering method based on cosine transform has the highest computing precision among these five methods, as shown by the comparison with the analytical algorithm, and the reasons of the error caused by these five kinds of conversion methods were discussed and analyzed, which is beneficial to the high precision calculation of one-dimensional forward modeling of transient electromagnetic response, so that these methods can be better applied to the calculation of multi-dimensional frequency-time conversion.